It is well known that lower back pain affects many adults, especially middle aged and older adults. As a consequence, a great deal of suffering and disability is experienced by a large fraction of the population resulting, among other things, lost workdays and greatly diminished quality of life.
A brief physiological analysis will help illustrate the cause of back pains and give an insight as to possible remedies.
The spinal column consists of thirty-three vertebrae which are joined together by cartilage tissue and ligaments. The upper twenty-four vertebrae are discrete and movable while the lower nine vertebrae are fixed. Five of the lower nine vertebrae are fused together to form the sacrum while the terminal four vertebrae are normally fused to form the coccyx. The normal spinal column may be considered to have seven cervical, twelve thoracic, five lumbar, five sacral, and four coccygeal vertebrae. Mobility of the vertebrae in the cervical, thoracic, and lumbar regions is relatively free compared with movement of the fused vertebrae of the sacrum and coccyx which is relatively constrained.
The main causes of common back pain are the continual stresses and strains experience by the lower back region which is the major, albeit not the sole, weight-supporting element of the upper body.
These stresses and strains eventually cause the damage symptomatic of back pain in that the cartilage material forming the discs separating the vertebrae is worn away over a period of time. In its extreme pathological condition, the patient may develop ankylosing spondylitis, namely, the partial, bent-down stiffening of the spinal column.
The sensation of pain is felt because the distance separating the vertebrae becomes narrower, causing pressure to be exerted on the nerve roots which extend from the spinal cord.
Due to the degenerative nature of the causes of back pain of this sort there is currently no permanent relief available, except for surgery where appropriate. There are, however, known procedures for the relief of pain in the lumbar region of the back. These procedures involve the stretching of the lower back to achieve the separation of the discs in the affected lumbar area. However, these treatments typically require the use of weights and other mechanical equipment and must be undertaken only under close professional supervision.
U.S. Pat. No. 5,772,612 to Daniel Ban, referred to above, discloses a device suitable for home use. With the '612 device, a user lies on a body-supporting surface with his or her knees over a frame, and the lower legs on a leg rest. The lower end of the device contacts the body-supporting surface, acting as a fulcrum. When the user pushes against the device, the device pivots so as to tend to lift the user's legs along a slightly arched path. A motor-driven version of the device is also disclosed.
The devices of the aforementioned '612 patent represent a useful attempt to provide a device for relieving lower-back pain suitable for home use. Specifically, with reference to FIGS. 1A-1C, a trained physiotherapist typically performs an initial lifting movement by raising the subject's legs from the position of FIG. 1A to that of FIG. 1B so as to neutralize the arched concavity of the back. This is followed by a primarily horizontal pulling motion (FIG. 1C), thereby applying tension tending to relieve pressure between the lumbar vertebrae. The tension is then released, thereby allowing the body to return under the action of gravity to a resting position.
U.S. Pat. Nos. 6,443,916 and 7,179,237, both to Ori Ilan, referred to above (the “Ori Ilan inventions” or the “'916 and '237 patents”), disclose another useful device for home use to help reduce and/or eliminate lower back pain.